Circulating tumor DNA (ctDNA) detection is associated with shorter progression-free survival in advanced melanoma patients

Gabriella Taques Marczynski,Rui Manuel Reis,Vinicius De Lima Vazquez,Ana Carolina Laus,Mariana Bisarro Dos Reis

doi:10.1038/s41598-020-75792-1

Gabriella Taques Marczynski, Rui Manuel Reis + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-75792-1

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Abstract

BRAF, NRAS and TERT mutations occur in more than 2/3 of melanomas. Its detection in patient’s blood, as circulating tumor DNA (ctDNA), represents a possibility for identification and monitoring of metastatic disease. We proposed to standardize a liquid biopsy platform to identify hotspot mutations in BRAF, NRAS and TERT in plasma samples from advanced melanoma patients and investigate whether it was associated to clinical outcome. Firstly, we performed digital polymerase chain reaction using tumor cell lines for validation and determination of limit of detection (LOD) of each assay and screened plasma samples from healthy individuals to determine the limit of blank (LOB). Then, we selected 19 stage III and IV patients and determined the somatic mutations status in tumor tissue and track them in patients’ plasma. We established a specific and sensitive methodology with a LOD ranging from 0.13 to 0.37%, and LOB ranging from of 0 to 5.201 copies/reaction. Somatic mutations occurred in 17/19 (89%) patients, of whom seven (41%) had ctDNA detectable their paired plasma. ctDNA detection was associated with shorter progression free survival (p = 0.01). In conclusion, our data support the use of ctDNA as prognosis biomarker, suggesting that patients with detectable levels have an unfavorable outcome.

Highlights

Melanoma is the most aggressive type of skin cancer due to the high occurrence of metastases and resistance to conventional chemotherapy[1]
A candidate biomarker that has been intensively evaluated is the circulating tumor DNA, which makes up part of cell-free DNA from p lasma[10,11]
Some relevant findings of this method include the association of circulating tumor DNA (ctDNA) levels to tumor burden in metastatic melanoma patients and the ability of baseline values to predict o utcomes[11,17,18]

Summary

Introduction

Melanoma is the most aggressive type of skin cancer due to the high occurrence of metastases and resistance to conventional chemotherapy[1]. To rapidly identify metastatic progression and appropriately select patients for more aggressive therapy and avoid unnecessary treatments, there is a need for more tumor biomarkers. In this context, a candidate biomarker that has been intensively evaluated is the circulating tumor DNA (ctDNA), which makes up part of cell-free DNA (cfDNA) from p lasma[10,11]. Some relevant findings of this method include the association of ctDNA levels to tumor burden in metastatic melanoma patients and the ability of baseline values to predict o utcomes[11,17,18]. The most frequently described mutations are C228T and C250T, which are mutually exclusive[24], but can co-occur with BRAF or NRAS mutations and are associated with lower s urvival[28,29,30]

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